Electromechanical interface for a typewriter



D. L. GREER 3,391,774

ELECTROMECHANICAL INTERFACE FOR A TYPEWRITER July 9. 1968 Filed July 17. 1967 DQNALD L. GREEN ATTORNEY.

United States Patent 3,391,774 ELECTROMECHANICAL INTERFACE FOR A TYPEWRITER Donald L. Greer, Lexington, Ky., assignor in International Business Machines Corporation, Armonk, N.Y., a corporation of New York Filed July 17, 1967, Ser. No. 653,783 Claims. (Cl. 197--19) ABSTRACT OF THE DISCLOSURE A low energy interposer bank is employed to deliver coded representations of characters to the selection mechanism of a single type matrix typewriter. The interposer bank includes an oscillating cage in which are slidably mounted a group of bidirectionally movable interposcr links. Electromagnets drive individual interposer links longitudinally within the cage to a position intersecting the path of oscillation of the cage to provide a positive mechanical connection for operating the typewriter selection mechanism. Manual control of the typewriter employs the same interposer links as a direct connection from an existing mechanical keyboard encoder.

Disclosure of the invention This invention provides a compact interconnection between 21 group of electromagnets designed for speed rather than power, and a corresponding group of binary mechanical input latches to a so-callcd whlifietree" character selector as described in US. Patent 2,919,002, issued Dec. 29, 1959, to L. E. Palmer and entitled, Selection Mechanism for a Single Printing Element Typewriter.

There are many constructions known for interconnecting electromagnets with typewriters for remote control. The value of any such interconnection can be measured by considerations of cost, speed of serviceability, and long term reliability. My construction optimizes these factors of value by employing a self-contained unit construction which is operable with parts manufactured to relatively wide tolerances and assembled in a self-aligning structure. The entire mechanism is removable as a unit for servicing and is sufficiently compact to fit within the normal covers of a standard oflicc electric typewriter. My construction employs the electromagnets as an information source only and does not require a power output of any significance therefrom. Furthermore, mechanical output from my interface is positively taken from a cam drive rather than relying on an impositive spring drive.

A principal phase of my invention involves the construction of a group of bidirectionally movable interposer links supported in an oscillating cage. Each interposer link is driven longitudinally within the cage by a flat electromagnet armature to provide a low friction rolling contact with the armature. Movement of the interposer link positions a drive surface in the path of oscillation of the cage to provide selective motion output therefrom.

These and other objects, features and advantages of my invention will be apparent to those skilled in the art upon reading the following description of a preferred embodiment of my invention wherein reference is made to the accompanying drawings of which:

FiGURE l is a side elevational view of a typewriter equipped with an electromechanical interface mechanism constructed in accordance with my invention wherein certain parts of the typewriter are broken away or eliminated for ease of understanding;

FIGURE 2 is a front elevational cross-sectional view 3,391,774 Patented July 9, 1968 of the interface mechanism shown in FIGURE 1 taken along lines 11-41 thereof;

FIGURE 3 is an enlarged fragmentary view of an interposer link and associated mechanism employed in my interface mechanism; and

FIGURE 4 is a partial side elevational view of a portion of the typewriter shown in FIGURE 1 which is separated therefrom for clarity.

Referring now more specifically to the drawing, in FIGURE 1 there is shown a typewriter or character-bycharacter printer T of basic construction like that described in aforesaid US. Patent 2,919,092. The typewriter T is characterized by a mold-character single type matrix or print element 10 having a plurality of character masters .11 positioned about its surface. The character masters 11 are selected by rotation and tilting of the element 10 and printing is accomplished by impact of the element 10 against a platen 12 at printing position 13. A whifiletree selection mechanism 14 (shown more comletcly in FIGURE 2 and more completely described in aforesaid Patent 2,919,002) serves to convert information provided in the form of a six bit parallel code, into a discrete combination of angular displacements of the element 10. The whifiietree mechanism 14 includes a plurality of dual input latches or hook control members 15 which control individual pull bars 16 of the whitiletree mechanism 14. A chopper bail or drive member 17 oscillates down and up each printing cycle to downwardly drive those latch members 15 positioned thereunder and thereby select an individual character master 11 for print- This invention deals with an input means or interface 29 for pulling selected latches 15 from under the path of the chopper bail 17 in response to electrical signals applied at input wires 31.

The interface mechanism 20 includes a plurality of vertically extending interposer links 40 which are individually connected, as by rods 18, to corresponding latches 15. The interposer links 40 are mounted for bidirectional movement in a cage or carriage 21. The cage 21 is pivotedly supported on the typewriter frame T: for reciprocating pivotal movement along a path 22 under the control of a half revolution cam 23 mounted on a selectively cyclically rotatable shaft 50 of the typewriter T.

As best shown in FIGURES 2 and 3, the interposer links 40 are longitudinally slidably supported on the pivot shaft 24 of the cage 21 by an elongated slot 41 and in a guide slot 25 that permits low friction movement of the interposer links 46 along individual paths 42 that are substantially normal to the path 22 of cage 21.

One end of a horizontally extending, magnetizable armature 32 (see also FIGURE 1) rollingly engages circular surface portion 43 of the interposer links 40 and is pivotally mounted at its other end by a slot 33 in a stationary bracket 34. A plurality of electromagnets or solenoid actuators 35 are individually positioned above, and between the ends of, respective armatures 32. When an armature 32 is magnetically attracted by its electromagnet 35, its left end is raised in the direction of interposer path 42. This movement raises an associated interposer link 40 against spring 44 to present a control shoulder or drive surface 45 in alignment with the cage 21 as shown by the broken line in FIGURE 3. Clockwise oscillation of the cage 21 about pivot axis 26 drives the raised interposer link 46 clockwise therewith to produce a pull on the connecting rod 18 connected thereto and move a latch 15 to its broken line position shown in llGURE 1. If, however. an interposer link 40 has not been lifted by its magnet armature 32. the space within the guide slot 25 will allow motion of cage 21 to be wasted, and no output will be produced at the respective pull rod 18. Obviously, the operation of the mechanism can be reversed by mounting interposer links in a normal position of interception with the cage 21 and selectively moving the interposed links to a position of non-interception therewith.

Input or control operation of electromagnets 35 is accompanied by generally simultaneous operation of a cycle-start electromagnet or solenoid actuator 36, see FIGURE 4. Electromagnet 36 pulls down on clutch latch trigger 51 to release clutch latch link 52 to move downwardly and to the right pulling holding-latch 53 from the sleeve of normally disengaged clutch 54. A cycle shaft 55 is thus connected to typewriter motor 56 through the clutch 54 all as more completely described in aforesaid U.S. Patent 2,919,002. Cycle shaft 55 is drivingly connected to the shaft for controlling cyclic motion thereof.

Operation of the mechanism thus far described is as follows: A source of parallel electrically coded data, such as from a magnetic tape unit as described in US. Patent 3,297,124, issued to D. E. Sims on Jan. 10, 1967, and entitled, Data Recording and Printing Apparatus Capable of Responding to Changed Format, operates the six electromagnets 35 and the clutch start electromagnet 36 to initiate rotation of shafts and 50. Substantially simultaneously therewith, the selectively activated electromagnets 35 pivot their respective armatures 32, and raise their respective interposer links 40 to the broken line position shown in FIGURE 3 wherein shoulder 45 lies in the path 22 of cage 21. Cam 23 rotates to bring a lift or rise portion 27 under cam follower 28 to positively drive follower 28 clockwise against its spring 29. Cage 21 is thus driven clockwise carrying with it those interposer links 40 which were previously raised by their armatures 32, while those interposer links 40 which were not lifted will remain relatively stationary. Any interposer link 40 which was lifted and hence intercepted by the cage 21 will pull its associated rod 18 to withdraw the respective latch 15 from under the chopper bail 17. Later in the cycle, chopper bail 17 will descend as described in aforesaid U.S. Patent 2,919,002 and pull downwardly on all latches 15 which have not been withdrawn as described.

It is also desirable that the typewriter T be operable from the usual keyboard 60 without interference from the electromechanical interface 20. The keyboard 60 shown in FIGURE 1 provides encoding means substantially like that shown and described in US. Patent 2,919,002. The keyboard 60 includes a plurality of individually depressable keybuttons 61 carried on keylevers 62 which activate associated encoding interposers 63 through non-repeat dobbers 64. The encoding interposers 63 have a selected plurality of downward projections 65 that cooperate with encoding bails or rods 66 to produce a mechanically coded binary representation of a character represented by a depressed key. Depression of keylever 62 depresses its associated encoding interposer 63. A clutch control bail 57 (see also FIGURE 4) is depressed by operation of any encoding interposer 63 to trip clutch latch trigger 51 and a cycle of operation is thus initiated. Cycle shaft 55 and shaft 50 are rotated and through a fluted drive portion 58, the depressed encoding interposer 63 is moved to the right of FIGURE 1 driving with it those encoding bails 66 which are adjacent the downward extensions 65.

My invention provides for the interposer links 40' to effect a direct connection from the mechanical encoder thus described to the latches 15 to provide for alternate remote or manual typewriter control. The encoding bails 66 thus are connected to respective ones of a group of transfer links or output members 67 which are individually associated with each of the bails 66. The transfer link 67 shown in FIGURE 1, for example, is provided with a downward projection 68 to the right of the leftmost bail 66. Accordingly, that transfer link 67 will move to the right each time that bail 66 is driven to the right by any of the encoding interposers 63. Rightward motion of the transfer link 67 is communicated to its respective selection latch 15 by a projecting hook 69 which engages a bent tab 46 of the associated interposer link 40 to provide a force transfer connection therebetween. Note that clearance 47 (see FIGURE 3) is provided between the hook 69 and tab 46 to eliminate interference by hook 69 with operation of the interposer link 40 by its electromagnet 35.

It will be recalled that a cycle of operation under control of the manual keyboard 60 included operation of the drive shaft 55. Accordingly, at the time that transfer link 67 is pulling interposer links 40 to the right, cam 23 will also be driving cage 21 to the right, out of the way of the interposer links 40.

Those skilled in the art will recognize that I have provided a compact, low cost electromechanical interface that is inherently reliable due to the continuous guiding and intercooperating relationship between the interposers and their support and drive cage. Also, it will be recognized that I have provided a unique mechanism for allowing both manual and electrical control of a typewriter selection mechanism. While a specific embodiment of my invention has been shown herein for purpose of illustration, it is to be understood that various modifications, additions, and deletions can be made thereto without departing from the scope and spirit of my invention as limited only by the appended claims.

I claim:

1. A printer having a multi-character print element that is differentially movable to selectively present different ones of a plurality of character masters to a printing position, and a plurality of dual input position control members cooperatively connected to said print element for controlling character selecting movement thereof, wherein the improvement comprises input means for selectively moving said control members between their dual positions and having:

a cyclically reciprocable cage movable along a predetermined path and having a plurality of guide slots therein,

a plurality of interposer links slidably mounted in the guide slots of said cage for movement along paths substantially normal to said cage path, each of said interposer links having a control shoulder surface extending substantially normal to said cage path,

means connecting individual ones of said interposer links to individual ones of said control members for moving said control members from one input position to the other input position thereof upon movement of said interposer links in the direction of said cage path, and

means for selectively individually moving said interposer links along said normal path to selectively position the respective control shoulder surfaces thereof in or out of said cage path.

2. A printer as defined in claim 1 wherein said control shoulder surface of said interposer link is normally positioned out of said cage path, and said individual interposer link moving means selectively moves its respective interposer shoulder surface into said cage path.

3. A printer as defined in claim 1 wherein said cage and interposer links are supported for movement in the direction of said cage path about a common pivotal axis.

4. A printer as defined in claim 1 wherein said means for moving said interposer links along said normal path comprises a plurality of electromagnets each associated with an individual one of said interposer links and being cooperatively connected therewith for moving its associated interposer link in one direction along said normal path, and spring means resiliently urging each of said interposer links in the other direction along said normal path.

5. A printer as defined in claim 4 wherein the improvement further comprises:

a keyboard having a plurality of individually depressable keybuttons,

a plurality of output members at least equal in numher to said interposer links and encoding means operable upon depression a keybutton for moving a combination of said output members repre sentative thereof, and

means connecting individual ones of said output members to respective ones of said interposer links to move the respective interposer links in the direction of said cage path upon movement of said associated output member.

6. A printer as defined in claim 3 having a motor, a selectively rotatable shaft and normally disengaged clutch means for selectively drivingly connecting said shaft with said motor wherein the improvement further comprises:

means responsive to depression of any of said keybuttons for causing engagement of said clutch means, and

further electromagnetic means operative substantially simultaneously with said first named electron-tag nets for alternatively operating said clutch engagement causing means.

7. A printer as defined in claim 6 further comprising:

a cam mounted on said shaft for rotation therewith,

said cam having a rise portion thereon,

a follower operatively engaging said cam and drivingly connected with said cage for moving said cage along 6 its path in an interposer link driving direction under control of said can: rise portion, and

a spring resiliently urging said follower against said cam for returning said cage along its path.

8. A printer as defined in claim 4 wherein said electromagnet connecting means comprises:

a magnetizable armature subflantially normal to said interposer link normal path and engaging said interposer link at the other end thereof, and

said electromagnet being positioned adjacent said armature between its pivoted support and interposer engaging end for pivotally displacing said armature by magnetic interaction therewith.

9. A printer as defined in claim I wherein each of said interposer links have a substantially circular surface portion for rollingly engaging their respective armatures.

10. A printer as defined in claim 9 wherein said cage and interposer links are supported for movement in the direction of said cage path about a common pivotal axis.

References Clled UNlTED STATES PATENTS 2,919,002 l2/l959 Palmer 197-16 3,233,715 2/1966 Flieg 197-19 3,353,744 11/1967 Becking et al l97--20 XR ROBERT E. PULFREY, Primary Examiner.

E. S. BURR, Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 ,391 774 July 9 1968 Donald L. Greer It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 3 line 5 "interposed" should read interposer Column 5, line 13, the claim reference numeral "3" should read 5 Signed and sealed this 20th day of January 1970 (SEAL) Attest:

Edward M. Fletcher, Jr. JR.

Attcsling Officer Commissioner of Patents 

